1. Field of the Invention
This invention relates to a novel method for the production of a colored macromolecular polymer. More particularly, this invention relates to a method for the production of a novel colored macromolecular polymer advantageously used as decorative organic plate glass, optical filter, and light shielding material in such fields as concerned with buildings, optical machines and tools, electrical appliances, and sundry goods.
2. Prior Art Statement
Heretofore, such macromolecular polymers as acrylic resin have been used often in a colored state. Their coloration has been generally attained by incorporation of organic dyes or pigments. When the macromolecular polymers colored by this method are used, particularly outdoors, they are inevitably discolored gradually on exposure to sunlight. This trend is particularly conspicuous when the coloration is red.
It is known that a finely divided metal powder absorbs light peculiar thereto. By virtue of this phenomenon, ceramic ware and glass ware are colored ["Colloid Chemistry", translated under supervision of Bunichi Tamamushi and published by Baifukan, page 398]. This coloration is attained by melting a salt of a given metal in combination with glass and subjecting the molten mixture to a reducing treatment or a reheating treatment. The product of this method has a red color when a gold salt or a copper salt is used or a red to yellowish brown color when a silver salt is used. The color tone assumed by the product depends on the finely divided metal powder contained therein and does not fade even after protracted exposure to sunlight.
As a way of dispersing a finely divided metal powder in a macromolecular polymer, a method which comprises reducing a noble metal salt into a corresponding metal colloid, displacing a dispersion medium of said colloid with a monomer, and polymerizing the resultant mixture (Japanese Patent Public Disclosure SHO 61(1986)-133202) has been known to the art. This method, however, is applicable only to rhodium, ruthenium, palladium, and platinum. Moreover, when the monomer used therein produces a macromolecular polymer, the product assumes a blackish brown to nearly black color and cannot be made to assume any other color. No method been known to the art which is available for effective dispersion of a finely divided powder of gold or silver as the source of a red or yellow color in a macromolecular polymer.
The present invention has been completed for the purpose of providing a method which permits a finely divided powder of such a noble metal as gold or silver in a macromolecular polymer and easily produces a colored macromolecular polymer safe from discoloration on exposure to sunlight.